# I get this error Expected Ptr<cv::UMat> for argument '%s' while resizing image in open cv2

This is my code:

# loading image from folder
folders = glob.glob('path to folder ')

imagenames_list = []

for folder in folders:
for f in glob.glob(folder+'/*.jpg'):
imagenames_list.append(f)

read_images = []

for image in imagenames_list:
read_images.append(cv2.imread(image, cv2.IMREAD_GRAYSCALE))

re_size = cv2.resize(read_images, (50,50), interpolation=cv2.INTER_LINEAR)


I get this error

Expected Ptr<cv::UMat> for argument '%s'


What does this mean and how can I fix it?

## 2 Answers

I changed the data type from float16 to float32, solving the problem:

images.astype(np.float32)

• not working for me.. – Shark Deng Jul 10 '20 at 15:22

I think your problem is because you are feeding a list instead of numpy array of image to cv2.resize.

re_size = [cv2.resize(img, (50,50), interpolation=cv2.INTER_LINEAR) for img in read_images]


should fix that for you.